Yesterday after I was done changing my oil my T/A would crank over but it would immediatly shut off..checked the batt connections they are good...I didn't add to much oil... I was thinking it might be a fuel related problem?Oh yeah I'm gonna check the maf now! Anyone have any ideas?

 

Fuel pump priming?

 

Any chance youi knocked off the electrical connection for the oil pressure sender right above the oil filter? I believe if the ECM doesn't see oil pressure it will shut down after a few seconds....

 

Naw I figured it out...my fuel pump went...any ideas how to replace it?

 

https://www.thirdgen.org/techbb2/sho...hreadid=265285

https://www.thirdgen.org/techbb2/sho...hreadid=264787

Im sure someone else can explain the real way on dropping the gas tank. But honestly im not gonna look, just do a if you don't want to do the trap door.

One thing I would do before ruling its the pump....Change the relay.

 

whats up pasky...I searched but came up with nothing...also what relay are you talking about?

 

The fuel pump relay

 

ok gentlemen how do I check the relay and where is it located?

 

It's one of the relays up under the hood near the power brake booster. I don't remember which one and they were different for different years/engines. I suppose you could pull one at a time and when you no longer get the fuel pump to prime when you turn the key then that's the one.

 

checked the relays they are good!

 

what up I'm about half way through taking my car apart! A great learning experince....I've got the exhaust off...Track bar off, track brace off, disconnected all fuel lines, the harness, now I'm taking off the rear sway bar...What will happen if I run the car with out the cat? Also there is a gold emmisions line the connects to the cat...what does it do? what will happen if I gut the cat?

 

just dropped the fuel tank and replaced the fuel pump...the car does the same thing...Any ideas now?fuel pump is fine I here it working...the fuel lines have fuel going thru them but I think its clogged some where...I think its the fuel filter

 

Early on your metioned checking the MAF but you didn't say if you got around to that (or how you checked it if you did).

As a quick and dirty test for a bad MAF to just unplug it and try starting the engine. If the MAF was bad the engine will now run, but the check engine light will be on, obviously. A start and immediate stall is classic bad MAF symptoms.

 

ok I'll try that thanks later on today

 

I unpluged the maf tried it the car still won't run...It turns overs but turns off immediatly

 

In-line fuel filter clogged?

 

I'm wondering if the fuel pump is being shut off because the ECM isn't seeing any oil pressure or RPMs (or something similar). ECM fires up the fuel pump automatically when cranking over with the starter but once it starts and begins to run on it's own the ECM looks at some stuff to keep the fuel pump running- I beleive an RPM signal from the distributor and oil pressure from the sender above the oil filter. Others could probably tell you exactly what it looks at, but those 2 jump to mind.

When you have this "start and then stall" does the fuel pump shut off and cause the engine to stall? Might be a good idea to put a FP gague on it and watch if you've got fuel pressure once it fires up. It's gotta be either fuel or spark- the engine wouldn't fire up if it was a mechanical problem inside the engine.

 

BTW- I'm starting to get a sinking feeling about this. I've been through threads like this before. It usually ends up with something like this: "So I tightened the license plate bolts and the engine suddenly started running perfectly again!"

In other words, it ends up being something that couldn't possibly have been figured out by reading the thread. I mean, other than knocking the connector off the oil pressure switch above the oil filter (or breaking the sender itself) there is just NO WAY an oil change could cause a problem like this. Are we getting the WHOLE story here?

 

Yeah I've been updating this thread as I do something...like today I pulled the ecm...Its not fuel related...is throwing a weird security code nac or noc or something like that...the ecm most likely isn't sending signal to the injectors to fire properly...so were testing the ecm

 

I replaced the ecm but retained the old prom! The car is throwing this weird anti-theft code...the car will start then shut down! Does anyone know about the security codes in these cars?

 

I know there are 15 different Vats security codes. If u think its a security reason; your car would even try to turn if your vats was working properly.

So I really doubt its that, and I also thought vats didnt come out till 89??

 

it throws a security code i have no idea wht it is

 

oil change should not cause this problem.....


how was the car running before the oil change? did you put oil in it? do you have oil pressure? is you oil pressure sender hooked up and working? did you do plugs or anything at the same time.

jeff

 

i'm gonna check the lock cylinder

 

Its coming up code 46...which is the code for VATS or the vech Anti theft System

So far we tested the key they are both good...The 5 volt input to the computer is good the 12 volt on the power input is good! Is there a way to by-pass the vats system? what should I do is there some sort of procedure? Also where is the Vats Control Module located?

 

If it was the VATS system I don't beleive it would even try to start. When I had a VATS problem on my Camaro absolutely NOTHING would happen when you turned the key. Not even a click. VATS only deals with starter de-activation, to my knowlege. I don't think it will shut off an engine once it's running. Perhaps someone more knowlegable could chime in on this.

 

It was the vats changed the ignition cylinder and key cranked it over and went cruising thanks guys The Don appreciated your help no more bumming rides from my little sister:rockon:

 

Weird...I also would have thought that VATS only disables a car from starting. When we were working on David's the other day and he turned the key, it jsut wouldn't start. All the lights would come on as normal but it would say "SECURITY" or "ANTI THEFT" whichever and nothing else....so he hotwired it

Though I suppose if it were malfunctioning, it could cause an issue like this especially since it was throwing the code...

 

I thought VATS started in '89. :shrug:

Any way, the easiest way to check the fuel pump for basic function (ie turns on and test static pressure) is to put 12v to the G terminal in the ALDL. I wish people would do that before going nuts with everything else.

 

Roughly 2/3 of GTA's received VATS in 1988. I know on my 1989 I dropped my key in the snow and my car would not crank. I guess 1988 was different?????

 

UA6. No kidding. Was it only the GTA's (only thing I can find RPO data on) and Vettes (IIRC they did start in 87 or 88) that got the UA6 option in 88? I would think it would operate the same as well. From reading the initial posts I was originally leaning toward a MAF relay. :shrug:

 

For reasons never explained to me the Camaro never received UA6 until 1989.

I guess his ignition must have been worn enough that an intermittent connection was being made at the resistor. I have heard of wires breaking behind the cylinder and shorting out as well. Ah the joys of 15 year old cars

 

It was probably finding a less resistant path to follow.

Maybe someone in DIY could pipe in if they ever came across any difference in the years for VATS. :shrug:

 

no It never even showed the security or check engine lite just threw a code 46...dunno